This invention relates to a receiver with an antenna switch known in the art. The receiver of the type is suitable for use in a mobile communication apparatus.
Such a conventional receiver is disclosed as a radio apparatus in, for example, Japanese Unexamined Utility Model Publication No. 34737/1993. The conventional receiver has been used in a TDD radio apparatus in order to implement the apparatus in a small size and at a low cost and to avoid deterioration in sensitivity upon reception of a high electric field.
However, the conventional receiver has a problem in which reception sensitivity is deteriorated by a switching operation of the antenna switch when the high electric field is supplied. The reason is as follows. In controtling the antenna switch, a same value is used as a reference level in common, both in switching from on to off, and in switching from off to on. Therefore, if the antenna switch is switched when the reception electric field level is not smaller than the reference level, the reception electric field level immediately becomes lower than the reference level. In this event, the switching condition of the antenna switch can not be maintained so that the high electric field is intermittently supplied to the receiving section. As a result, it is impossible to obtain a stable reception signal.